Na1.5Bi2.5Nb3O12 powders which are high crystallinity and perfect fine-grains are prepared by hydrothermal method using Nb2O5, Bi2O3, NaOH as aw materials, and KOH serves as a mineralizer with the addition of ethylene glycol. The influence of the reaction temperature and the reaction time on the phase structure is analyzed by means of X-ray diffraction (XRD). The morphology of Na1.5Bi2.5Nb3O12 is analyzed by scanning electron microscopy (SEM). The results show that pure Na1.5Bi2.5Nb3O12 plates-layered structure powders with the average thickness of 50nm and diameter of 200 nm are synthesized at the reaction temperature of 160 ℃ and the reaction time of 18 h.